#include <reg51.h>
#include <intrins.h>  

//delay
void delay(unsigned int i)      
{      
	unsigned int k;
	for (k=0;k<i;k++);
}
void main()                       
{                                         
	P0 = 0xff;                 
	while(1)                      
	{                                 
		P0 = P0 | (1<<0);   
		delay(5000);    
		P0 = P0 & (~(1<<0));    
		delay(5000);   		
	}                                     
}                                              

